Spring construction



Jan. 1 7, 1956 H. C. FLINT SPRING CONSTRUCTION Filed Aug- 2, 1949 FTw'ZIVEXi 2,731,075 -Patented Jan. 17, 1956- SPRING CONSTRUCTION HylandC. Flint, Birmingham, Mich., assignor to American Metal ProductsCompany, Detroit, Mich., a corporation of Michigan Application August 2,1949, Serial No. 108,133

Claims. (Cl. 155-479) This invention relates to spring constructionsembodying a plurality of prearched, sinuous, or zigzag spring strips ofthe type disclosed and claimed in Kaden Reissue Patent No. 21,263 and,in particular, refers to such a spring per se.

Sinuous spring strips of the type indicated have become increasinglypopular in recent years for use in spring cushion constructions because,among other reasons, of the ease with which they can be adapted toprovide various cushioning characteristics. For example, as shown in acopending application, Serial No. 89,114, filed April 22, 1949, nowPatent No. 2,698,651, issued November 30, 1954 of the present inventor,entitled Zigzag Spring Unit Having a Closed Supporting End,

there are disclosed a number of spring strip constructions which providevarying types of conformability to objects placed thereon. This isaccomplished by bolstering up desired sections of the spring stripsthrough the medium of additional resilient supports attached thereto.There are instances, however, where, instead of stiffening the springstrip, as in the invention of the application just mentioned, it isdesired to soften the spring.

This, for example, is the case when the convex bodyengaging portion ofthe spring substantially intersects or is slightly below and facing therail. In such a case,

limitations on the depth of the spring construction nor;

mally prevent the use of conventional types of resilient supports forthe end of the strip and it therefore is necessary to resort to meanssuch as provided by this invention for attaching the strip to the railin such a manner that the spring is softened.

The general object of this invention is, therefore, to provide means forsoftening sinuous spring strips of the type referred to.

A more particular object is to provide means for attaching the arcuateseating portion of a sinuous spring to a rail which furnishes increasedflexing and softness and also permits the convex side of the seatingportion to substantially intersect or face the rail.

These and other objects of the invention are accomplished by a sinuousspring strip construction having a deformable section or buckle adjacentthe end which is to be fixed to the cross rail. The buckle is preferablysubstantially V-shaped and defined by side portions which are movablerelative to each other so as to provide the necessary increase inflexing required to soften the spring strip.

Various forms of the invention are shown by way of illustration in theaccompanying drawings, in which:

Figure 1 is a side elevation of one form of spring strip embodying theinvention which is attached at each end to the usual cross rails thatare shown in section;

Fig. 2 is an enlarged view of the portion of the spring strip of Fig. 1included within the circle 2;

' Fig. 3 is a partial plan view of the spring strip of Fig. 1 and showsthe sinuous or zigzag construction; and

Figs. 4, 5, 6 and 7 are views similar to that of F1g. 2

of modified forms of the invention.

The spring strip 1 of Figs. 1 and 2 has a web portion 3 which issupported underneath one end by a conventional outwardly opening Vsection 5 formed in the spring strip and is attached to the rail 7 byinsertion of the straight portion of the last of the adjacent,oppositely presenting loops 9 in a clip 11 of conventional form that issecured to the rail 7. Spacer loops 13 may be provided between thesupport 5 and the web and also at the apex of the support 5 to increasethe depth of the spring construction. .If desired, a helper spring 15may be clipped at its ends to the web 3 after prearching onsubstantially the same radius as the web so that it lies injuxtaposition to the strip 1 and thereby increases the stiifness of thecentral portion of the web 3.

In accordance with this invention, means are provided to increase thepermissible flexing, particularly in a longitudinal direction, of theother end or" the spring, this end being attached to the rail 17 in sucha manner that the convex upper face of the web or seating portion 3, ifextended, would intersect the rail. This end of the spring is rigidlyaflixed to the top of the rail 17, preferably by insertion of an entiresingle loop 9 in clip 19 having a form which is described and claimed ina copending application Serial No. 88,293, filed April 19, 1949, nowPatent No. 2,695,658, issued November 30, 1954, of the present inventor,entitled Spring Supporting Clip Having Locking Tongue. Between themember 9 which is mounted in the clip 19 and the web 3, a buckle 21 isformed in the strip 1. In the present embodiment, the buckle comprisesan upwardly opening V having its apex below the rail 17. The buckle 21has an outer side portion or leg 23 which is somewhat shorter than theinner leg 25; for the sake of illustration, it be ing shown asconsisting of two loops 9 While the inner leg 25 consists of three loops9. By virtue of this construction the application of a load P to the web3 causes the angle included between the legs 23 and 25 to increase.This, of course, increases the effective length of the strip 1 and tothis extent decreases its resistance to the load P and increases thestrips softness. The expansion of the angle between legs 23 and 25 isaccommodated inmost part by twisting or torsion of three rectilinear legportions of the loop 9, viz., at the point 27 where the leg 25 connectswith the web 3, the point 29 where the legs 23 and 25 intersect, and thepoint 31 where the leg 23 connects with the loop 9 that is inserted inthe clip 19. As a result of this twisting, the point 29 is pivotedoutwardly about the point 31 to flatten the spring 1 and permit theconvex surface of the web 3 to drop well below and face the top of therail 17.

The spring strip 41 shown in Fig. 4 has a buckle 43 between the web 45and the endmost loop 47 which is substantially V-shaped and opensdownwardly. In this embodiment the rectilinear end portion of the endloop 47 is pivotally secured to the underside of a rail 49 by means of asuitable clip 51 which also has a horizontal shoulder 53 against whichthe balance of the loop 47 abuts. The outermost leg 55 of the buckle 43extends more or less vertically from the loop 47 and in this case is ofsubstantially the same length as the inner leg 5?. Upon application of aload to the web 45, the buckle 43 will open as shown in dotted lines inFig. 4 and the spring will pivot about the clip 51, the combination ofthese effects providing substantial deflection of the web 45.

In the embodiment of Fig. 5, the spring strip 61 has a web 63 thatincludes a buckle 65. The buckle 65 may also be V-shaped, but in thiscase it opens outwardly so that the apex and also a side portion aredisposed above a portion of the web 63. The upper leg 67 of the buckle65 is, in unstressed position, substantially horizontal and connectswith a loop 9 that is rigidly secured to the rail 69 by means of a clip19. The other leg 71 of the buckle 65 extends upwardly and inwardly froma loop "/3 that is formed outwardly and upwardly from the convex surfacedefined by the web 63. Upon application of the load to the Web 63, thespring 61 is deflected elastically to the dotted-line position of Fig.5. Expansion of the buckle 65 and twisting of the end portions thereofthat are connected to the endmost loop in clip 19 and to the loop 7.3,as well as twisting of the rectilinear loop portion forming the apex ofthe buckle, provide a substantial increase in the permissible flexingover that obtainable with a continuous web construction, and furtherpermits the convex surface of web 63 to lie well below and face a planethrough the front and rear rails.

In the embodiment shown in Fig. 6, the spring strip 81 has a web 83which is connected through the buckle 85 to an upper and outer portionof the rail 87 by means of a clip 19 which rigidly holds the endmostloop 89. The buckle 85 is V-shaped with the apex above the web 83 andopens downwardly on the rail 87. The outer leg 91 of the buckle 85 liesin the plane of the endmost loop 89, and the inner leg 93 intersects theweb 83 in a slightly obtuse angle. As will be apparent from thedotted-line position of the spring in Fig. 6, which shows itsconformation after a load is applied thereto, the buckle 85 is in thisform contracted or closed by the application of the load. As far as theweb 83 is concerned, contraction of the buckle 85 has the same result asexpansion of the buckles described in the preceding embodiments, i. e.,increases the effective length of the strip 81 and thus decreases theresistance to the load.

In the embodiment of Fig. 7, the strip 101 has a web 103 which isconnected to the rail 105 through a U or talon-shaped buckle 107 havingits apex or heel portion above the web 103 and embracing the rail 105.The endmost loop of the strip 101 is secured by a clip 19 to theunderside of the rail 105. As evidenced by the dotted-line position ofthe strip 101 (Fig. 7), application of the load causes increased flexingof the strip due to contraction of the buckle 107. In this particularembodiment the buckle 107 also serves to provide a resilient enclosurefor the rail 105.

From the foregoing illustration of the various forms of the invention itwill be realized that the buckles, by virtue of their ability to expandand contract, endow the strips with an additional amount of deflectionunder load which results in softening of the strip ends that areadjacent to the rigid rails. While it is ordinarily the endmost portionsof the strips which require increased flexing such as provided by thebuckles, it will be recognized that they may be used in intermediateportions of the spring, if desired, Without departing from the spirit ofthe invention. Other forms of buckles, as well as other modifications ofthe invention, will appear to those in the art; hence it is not desiredto limit it to the specific details shown here by way of illustration.

What is claimed is:

1. A sinuous or zigzag spring strip having a convex load-supportingportion and a substantially V-shaped buckle formed in the strip, theapex above the convex portion and the mouth thereof facing the convexportion, the buckle being disposed adjacent to a rear rail element of asupport when the spring strip is assembled thereon, the bucklepermitting longitudinal extension and vertical deflection of the loadsupporting portion of the spring strip.

2. A sinuous or zigzag spring strip having a convex load-supportingportion and a talon-shaped buckle formed in the strip with the basethereof above the convex portion, said buckle being disposed adjacent toa rail element of a support when the spring strip is mounted thereon,the buckle permitting longitudinal extension and vertical deflection ofthe load supporting portion of the spring strip.

3. In a spring seat construction, the combination of a horizontal rearrail, a prearched zigzag spring strip having a load bearing portionextending over a substantial portion of the length of the strip and alsohaving a rear support portion fixedly secured to the rail formed incontinuation of the load bearing portion, the rear section of said loadbearing portion being substantially no higher than a horizontal planethrough the rear rail, said rear support including a deformable buckleenabling said load bearing portion to move lengthwise toward the rearrail as Well as transversely when load is applied thereto, said bucklecomprising a portion of the strip bent at an angle to the plane of saidrear section and then reversely bent to extend back toward said plane,said buckle portion having an apex located on one vertieal side of therear section and an expansible and contractible mouth locatedsubstantially in the plane of the rear section, said buckle portionbeing bent at an included angle of more than degrees with respect to theplane of said rear section and extending only rearwardly from said rearsection.

4. The invention set forth in claim 3 wherein said apex is spacedvertically above the plane of the rear section.

5. The invention set forth in claim 3 wherein said apex is spacedvertically below the plane of said rear section.

References Cited in the file of this patent UNITED STATES PATENTS2,125,987 Braun Aug. 9, 1938 2,177,175 Freund Oct. 24, 1939 2,257,633Bank Sept. 30, 1941 2,285,827 Neely June 9, 1942 2,526,183 Williams eta1 Oct. 17, 1950 FOREIGN PATENTS 206,149 Switzerland Oct. 16, 1939210,373 Great Britain Jan. 31, 1924

